Method for calculating the pressure holding and pressure building time of closed device based on explosion wave simulation device

Abstract

The present invention relates to the technical field of pressure holding test for closed devices, and discloses a method for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device, comprising: obtaining the charge amount, detonation point cross section, closed cross section area, space volume and inlet area and volume of the explosion wave simulation device; calculating the incident overpressure of the incoming flow according to the charge amount, detonation point cross section, closed cross section area and space volume, further calculating the reflected overpressure of the incoming flow, and determining the initial pressure relief coefficient; determining the final pressure relief coefficient according to the pressure difference between the final inflation relative pressure of the closed device and the reflected overpressure of the incoming flow, and further determining the average pressure relief coefficient; calculating the pressure holding and pressure building time according to the inlet area, volume and final inflation relative pressure of the closed device and the average pressure relief coefficient. The present invention proposes a method for calculating the pressure increase time and input pressure in a closed device using the airflow generated by the explosion wave simulation device, which can provide a basis for the pressure holding test of the closed device.

Description

Technical Field

[0001] The invention relates to the technical field of pressure holding test for closed devices, and in particular to a method for calculating the pressure holding and pressure building time of a closed device based on a blast wave simulation device. Background Art

[0002] The pressure holding test of closed devices is generally divided into static water pressure and dynamic inflation. For conventional closed devices, the static water pressure test can meet the requirements; because the structural response under dynamic load is obviously different from that under static load, for closed devices subjected to dynamic load, it is necessary to verify the strength of the structure through necessary dynamic pressure holding test.

[0003] The rocket engine interstage separation test is a dynamic pressure holding process. The design pressure during the interstage separation is the main condition for controlling the timing. When the design pressure is reached, the cutting rope completes the cutting and separation according to the predetermined timing. At present, most rocket engine interstage separation tests use the "three-in-one" test. This type of test has formed a relatively mature calculation method, which can achieve a relatively accurate prediction of the cutting time. In recent years, the jet process of rocket engines has been simulated by explosion wave simulation devices, which can also better simulate the interstage separation process. However, there is currently no corresponding relationship between pressure and time during the inflation of the closed device using the explosion wave simulation device. The boost time can only be determined through a large number of debugging tests, which affects the efficiency of the explosion wave simulation device in the rocket engine interstage separation test.

[0004] As mentioned above, there is no method to guide the calculation of the relationship between the internal pressure increase and time of a closed device during the pressurization test using an explosion wave simulation device. It is difficult to predict the time of pressure increase and the separation time between rocket stages cannot be effectively determined.

[0005] Therefore, it is an urgent problem for technical personnel in this field to provide a method for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device to solve the difficulties existing in the prior art. Summary of the invention

[0006] The purpose of the present invention is to provide a method for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device, which can predict the pressure value of the closed device under different loading times and provide technical support for opening the closed device at a predetermined time.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A method for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device comprises the following steps:

[0009] S1, obtaining the charge amount, detonation point cross section, closed cross section, space volume and inlet area and volume of the closed device of the explosion wave simulation device;

[0010] S2, the incident overpressure is calculated based on the charge amount, detonation point cross section, closed cross section and space volume of the explosion wave simulation device;

[0011] S3, calculate the incoming reflected overpressure according to the incoming incident overpressure and determine the initial pressure relief coefficient;

[0012] S4, determine the final pressure relief coefficient based on the pressure difference between the reflected overpressure of the incoming flow and the final inflation relative pressure of the closed device;

[0013] S5, determining an average pressure relief coefficient according to the initial pressure relief coefficient and the final pressure relief coefficient;

[0014] S6, calculate the pressure holding and pressure building time according to the inlet area and volume of the closed device, the final inflation relative pressure of the closed device and the average pressure relief coefficient.

[0015] Furthermore, the S2 is calculated based on the charge amount, the detonation point cross section, the closed cross section area, and the space volume to calculate the incident overpressure using the following formula:

[0016]

[0017] in, P i is the inflow overpressure, V t is the spatial volume, γ is a coefficient related to the performance of explosives, α is a coefficient related to the distance from the measuring point to the detonation point and the equivalent diameter of the cross section at the measuring point, β is the coefficient related to the ratio of the cross-sectional area at the detonation point to the cross-sectional area at the measurement point, A c is the detonation point cross section, A j is the cross-sectional area of ​​the closed part, Q For the charge amount.

[0018] Further, the S3 includes: S301, calculating the incoming reflected overpressure according to the incoming incident overpressure, using the following formula:

[0019] P r = 2 P i + 6 P i 2 / ( P i+ 7 P 0 )

[0020] in, P r is the reflected overpressure of the incoming flow, P 0 is atmospheric pressure.

[0021] Furthermore, the S3 further includes: S302, calculating the initial pressure relief coefficient according to the reflected overpressure of the incoming flow, using the following formula:

[0022]

[0023] in, CL 1 is the initial pressure relief coefficient 。

[0024] Furthermore, the S4 includes: S401, calculating the pressure difference between the reflected overpressure of the incoming flow and the final inflation relative pressure of the closed device, using the following formula:

[0025] ,

[0026] in, ΔP h is the pressure difference, P It is the final inflation relative pressure of the closed device.

[0027] Furthermore, the S4 further includes: S402, calculating the final pressure relief coefficient according to the pressure difference, using the following formula:

[0028]

[0029] in, CL 2 The final pressure relief coefficient 。

[0030] Furthermore, in S5, according to the initial pressure relief coefficient and the final pressure relief coefficient, an average pressure relief coefficient is determined using the following formula:

[0031]

[0032] in, CL is the average pressure relief coefficient, CL 1 is the initial pressure relief coefficient, CL 2 is the final pressure relief coefficient.

[0033] Furthermore, in S6, the pressure holding and pressure building time is calculated according to the inlet area and volume of the closed device, the final inflation relative pressure of the closed device and the average pressure relief coefficient, using the following formula:

[0034]

[0035] in, t The time for holding pressure and building pressure. V is the volume of the closed device, S is the inlet area of ​​the closed device, P It is the final inflation relative pressure of the closed device.

[0036] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0037] The method proposed in the present invention for calculating the pressure-building time of a closed device based on an explosion wave simulation device can accurately calculate the dynamic pressure-building time of a closed device under the loading condition of the explosion wave simulation device, and can predict the pressure value of the closed device under different loading times, providing technical support for the opening of the closed device at a predetermined time. The present invention proposes a method for calculating the pressure increase time and input pressure in a closed device using the airflow generated by an explosion wave simulation device, which can provide a basis for the pressure-building test in such closed devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0039] Figure 1 A schematic diagram of the pressure holding test structure of the closed device in the explosion wave simulation device provided by the present invention;

[0040] Figure 2 A flow chart of a method for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device provided by the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The purpose of the present invention is to provide a method for calculating the dynamic pressure building time of a closed device in an explosion wave simulation device, and proposes a method for calculating the pressure increase time and input pressure in a closed container loaded by the airflow generated by the explosion wave simulation device, which can provide a basis for the pressure building test in such a closed device.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] The present invention provides a method for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device, comprising the following steps:

[0045] S1, obtaining the charge amount, detonation point cross section, closed cross section, space volume and inlet area and volume of the closed device of the explosion wave simulation device;

[0046] S2, the incident overpressure is calculated based on the charge amount, detonation point cross section, closed cross section and space volume of the explosion wave simulation device;

[0047] S3, calculate the incoming reflected overpressure according to the incoming incident overpressure and determine the initial pressure relief coefficient;

[0048] S4, determine the final pressure relief coefficient based on the pressure difference between the reflected overpressure of the incoming flow and the final inflation relative pressure of the closed device;

[0049] S5, determining an average pressure relief coefficient according to the initial pressure relief coefficient and the final pressure relief coefficient;

[0050] S6, calculate the pressure holding and pressure building time according to the inlet area and volume of the closed device, the final inflation relative pressure of the closed device and the average pressure relief coefficient. Example

[0051] The present invention takes a certain explosion wave simulation device to carry out a certain rocket engine interstage separation test as an example, and the structure diagram is as follows Figure 1 As shown. Figure 2 As shown, the method for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device provided in this embodiment is as follows:

[0052] Step 1: Measure the detonation point cross section of the blast wave simulation device A c , closed cross-sectional area A j , space volume V t and the inlet area of ​​the enclosure S ,volume V The detonation point cross section of a certain explosion wave simulation device in this embodiment A c0.502m 2 , closed cross-sectional area A j 0.342m 2 , space volume V t 12.60m 3 , the inlet area of ​​the closed device S 0.018m 2 ,volume V 1.00m 3 .

[0053] Step 2, according to the charge amount Q and step 1 A c , A j , V Calculate the inflow overpressure P i The charge amount this time is 14.35Kg.

[0054] In step 2, the incoming overpressure P i The calculation formula is:

[0055]

[0056] In the formula, γ, α、β The constants can be obtained according to conventional techniques in the art. α、β The above three constants have been determined through experiments, and the above formula becomes:

[0057]

[0058] In step 1 A c =0.502m 2 , A j =0.342m 2 , V t =12.60m 3 as well as Q =14.35Kg Substituting into the above formula, we can get the inflow overpressure P i The pressure value is 1217.095KPa.

[0059] Step 3: According to the inflow overpressure in step 2 P i Calculate the reflected overpressure of incoming flow P r .

[0060] Incoming flow reflection overpressure P r The calculation formula is:

[0061]

[0062] Wherein, P 0 is atmospheric pressure, generally 100KPa, and the pressure in step 2 is P i =1217.095KPa Substituting into the above formula, we can get P r It is 9732.57KPa.

[0063] Step 4: Calculate the initial pressure relief coefficient based on the reflected overpressure CL 1 .

[0064] The calculation formula for the initial pressure relief coefficient in step 4 is:

[0065]

[0066] In step 3 P r =9732.57KPa Substitute into the above formula CL 1 =0.145 P r +43.883, we get CL 1 1455 KPa.m / ms .

[0067] Step 5: Based on the final relative pressure of the closed device P， Calculate the pressure difference between the reflected overpressure of the incoming flow and the final relative pressure of the closed device ΔP h .

[0068]

[0069] The final inflation relative pressure in this embodiment P For 350 KPa , it can be considered that the reflected overpressure of the incoming flow remains unchanged. P r =9732.57KPa, P =350 KPa Substituting into the above formula, we can get ΔP h is 9382.57 KPa .

[0070] Step 6: According to the pressure difference in step 5 ΔP h Calculate the final pressure relief factor CL 2 .

[0071] The final pressure relief coefficient calculation formula is:

[0072]

[0073] In step 5 ΔP h =9382.57KPa Substitute into the above formula CL 2 =0.145 ΔP h +43.883, we get CL 2 1404 KPa.m / ms .

[0074] Step 7: According to the initial pressure relief coefficient in step 4 CL 1 and the final pressure relief factor in step 6 CL 2 Calculate the average pressure relief factor CL .

[0075] Average pressure relief coefficient in step 7 CL The calculation is done using the following formula:

[0076]

[0077] Set the pressure relief factor in step 4 CL 1 =1455 KPa.m / ms and the pressure relief coefficient in step 6 CL 2 =1404 KPa.m / ms Substituting into the above formula, we can get CL 1429.5 KPa.m / ms .

[0078] Step 8: According to the inlet area of ​​the closed device in step 1 S and volume V , the final relative inflation pressure in step 5 P And the average pressure relief coefficient in step 7 CL Calculate the pressure holding and pressure building time t .

[0079] Specifically, the pressure holding and pressure building time t The calculation is done using the following formula:

[0080]

[0081] In step 1 S =0.018m 2 , V =1.00m 3 , in step 5 P =350 KPa , in step 7 CL = 1429.5 KPa.m / m Substituting into the above formula, we can get the pressure holding and pressure building time t It is 13.60ms.

[0082] The present invention can also provide a system for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device, which is used to execute the above method.

[0083] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0084] The remaining technical features in this embodiment can be flexibly selected by those skilled in the art according to actual conditions to meet different specific practical needs. However, it is obvious to those skilled in the art that it is not necessary to adopt these specific details to implement the present invention. In other examples, in order to avoid confusing the present invention, the well-known components, structures or parts are not specifically described, which are all within the technical protection scope defined by the technical solution claimed for protection in the claims of the present invention.

[0085] Modifications and changes made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the scope of protection of the claims attached to the present invention. In the above description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that these specific details are not necessary to practice the present invention. In other examples, in order to avoid confusing the present invention, well-known technologies, such as specific construction details, operating conditions and other technical conditions, are not specifically described.

[0086] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device, characterized in that: The following steps are involved: S1, obtaining the charge amount, detonation point cross section, closed cross section, space volume and inlet area and volume of the closed device of the explosion wave simulation device; S2, according to the charge amount of the explosion wave simulation device, the cross-section of the detonation point, the cross-sectional area of ​​the closed part, and the volume of the space, the incident overpressure is calculated using the following formula: ， in, P i is the inflow overpressure, V t is the space volume, γ is a coefficient related to the performance of explosives, α is the coefficient related to the distance from the measuring point to the detonation point and the equivalent diameter of the cross section at the measuring point, β is the coefficient related to the ratio of the cross-sectional area at the detonation point to the cross-sectional area at the measurement point, A c is the detonation point cross section, is the cross-sectional area of ​​the closed part, Q is the charge amount; S3, calculating the incoming flow reflected overpressure according to the incoming flow incident overpressure, and determining the initial pressure relief coefficient; wherein the initial pressure relief coefficient is calculated according to the incoming flow reflected overpressure, using the following formula: ， ， in, CL 1 is the initial pressure relief coefficient, P r Overpressure reflected by incoming flow; S4, according to the pressure difference between the reflected overpressure of the incoming flow and the final relative pressure of the closed device, determine the final pressure relief coefficient using the following formula: ， ， in, CL 2 is the final pressure relief coefficient, ΔP h is the pressure difference; S5, determine the average pressure relief coefficient based on the initial pressure relief coefficient and the final pressure relief coefficient CL ; S6, calculate the pressure holding and pressure building time based on the inlet area and volume of the closed device, the final inflation relative pressure of the closed device and the average pressure relief coefficient, using the following formula: ， in, t It is the time for holding pressure and building pressure. V is the volume of the closed device, S is the inlet area of ​​the closed device, P It is the final inflation relative pressure of the closed device.

2. The method for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device according to claim 1 is characterized in that: The step S3 includes: calculating the reflected overpressure of the incoming flow according to the incident overpressure of the incoming flow, using the following formula: ， in, P r is the reflected overpressure of the incoming flow, P 0 is atmospheric pressure.

3. The method for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device according to claim 2 is characterized in that: The step S4 includes: calculating the pressure difference between the reflected overpressure of the incoming flow and the final relative pressure of the closed device by using the following formula: ， in, ΔP h is the pressure difference, P It is the final inflation relative pressure of the closed device.

4. The method for calculating the pressure holding and pressure building time of a closed device based on an explosion wave simulation device according to claim 1, characterized in that: In S5, the average pressure relief coefficient is determined according to the initial pressure relief coefficient and the final pressure relief coefficient, using the following formula: ， in, CL is the average pressure relief coefficient, CL 1 is the initial pressure relief coefficient, CL 2 is the final pressure relief coefficient.

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